The optical fiber communication device has been widely used in high speed communication networks. Especially with the rapid development of the high-speed local area network and fiber optic networks, the demand of optical fiber communication systems increases. In optical fiber communication devices or systems, optoelectronic transceiving modules are installed in communication equipments for optical signal transformation and transmission. In order to increase system design flexibility and easy maintenance, optoelectronic transceiving modules are inserted to the communication device in a pluggable way. The optoelectronic transceiving modules or devices require miniaturization along with the rapid development of optical fiber communication technology, and the performance thereof can not be degraded due to their size getting smaller.
Optoelectronic transceiver is the core component of the optoelectronic transceiving module. Therefore, the miniaturization of optoelectronic transceiving module usually depends on the size of optoelectronic transceiver.
There are known different types of optoelectronic transceivers in traditional optical fiber communications. FIG. 1 shows a conventional optoelectronic transceiver 1A, comprising a transmitting laser diode 1, an optical sensor 2, and a card access/physical connection type (referred to as SC/PC) fiber adapter 3. When optoelectronic transceiver 1A connects with external optical communication device, the connector 4 connects with a fiber 5a. The other end of fiber 5a inserts to an APC (angled physical contact)/APC type fiber adapter 6, and connects to external optical communication system. In such optical transceivers, the light emitted from the laser diode 1 pass through the fiber adapter 3, the fiber 5a, and the fiber adapter 6, therefore, the power loss of the optical signal through above path achieves 0.3 dB to 0.4 dB. In addition, the return reflection loss of the end of the optical adapter 3 is poor. This level of power consumption for high transmission rate such as 2.5 GHz communication applications is not acceptable.
FIG. 2 shows another known fiber bi-directional optoelectronic transceiver, also called pigtail fiber bi-directional optoelectronic transceiver 1B. FIG. 2 shows a pigtail fiber bi-directional optoelectronic transceiver 1B comprising a transmitting laser diode, an optical sensor 10, a ceramic ferrule 11, and a fiber 5c. When optoelectronic transceiver 1B connects with external communication networks, one end of the fiber 5c leading from the body inserts into an APC/APC type fiber adapter 12 and connects to the optical communication networks. The curled fiber 5c, in pluggable bi-directional optoelectronic transceiver 1B, is configured to resolve power reflection loss. However, the radius of the curled fiber 5c has to be more than 15 mm, generally 30 mm. Therefore, the volume of optoelectronic transceiver 1B increases inevitably, and adversely affects the miniaturization of the overall module.
Moreover, in the prior art, in order to resolve the problem of low coupling efficiency of the laser diode, the power of the laser diode will be increased. But this will increase the cost. Or, use 6 degrees or less with the end angle of the ceramic ferrule, but this will cause unstable transmission due to poor return loss. Generally, the ceramic ferrule is made of a hollow ceramic shell and a fiber set in the core of the hollow ceramic shell. The end of the ceramic ferrule is polished at a specified angle, such as 6 degrees.
Therefore, a pluggable bi-directional optoelectronic transceiver with small size, low loss, and low cost is required.